The present invention relates to retaining components in a housing. In particular, the invention is directed to a system, such as a hydraulic control unit, wherein an attenuator cap is contained within an opening of the unit housing by seating the cap against an angled stop in the bore of the unit and deforming a portion of the housing over the cap.
A hydraulic control unit of a vehicle braking system typically includes a number of devices that cooperate to control fluid pressure in a vehicular braking system, and in particular in an anti-lock braking system. Many of the devices, which include solenoids, valves, pumps, attenuators, and so on, are housed in a central unit hydraulic housing.
A hydraulic control unit includes a body or housing having bores for mounting various components therein as well as channels for directing fluid. For example, an attenuator is mounted in a bore in the hydraulic control unit. The use of attenuators that reduce the amplitude of pressure fluctuations in hydraulic fluid lines of vehicular braking system is well known. In particular, attenuators are common in vehicular anti-lock braking system (ABS) at the outlet end of an ABS hydraulic pump used to generate supplemental brake fluid pressure.
Generally, shown in FIG. 1, a prior art system of retaining a component, an attenuator cap, in a hydraulic control unit housing 8 is shown. An isolated bore 12 is shown which can be one of a plurality of bores in the unit. The attenuator cap 10 and bore 12 together define a chamber 14 with a predetermined volume that allows compression of brake fluid in the chamber 14. This significantly reduces the amplitude of high-energy pressure pulses in the brake fluid at the outlet of the pump (not shown). Such devices require an effective means for accurately positioning and retaining the cap 10, and therefore the pressure pulses produced within the bore.
Conventional attenuator caps 10 and similar components that are mounted in a hydraulic control unit are typically positioned in the bore 12 by some form of a positive stop 16. The positive stop 16, which is typically an annular, radially extending land with a face 18 at right angles to the axial direction, cooperates with a radial shoulder or face of the component 10 to seat the component 10 in the bore 12. A staking process can be used to retain the component in the housing 8 by deforming adjacent housing material 22, and closing the diameter of the bore, after the component is positioned within the housing. In the alternate, a circular clip, snap clip or circlip (not shown) retains the component 10. In part, due to the necessity of forming the positive stop 16, the larger diameter countersunk portion 17 of the bore, is necessary. This large diameter portion 17 requires a relatively large amount of space between components, and thus, a relatively large housing. In the case of the use of a threaded attachment or retainer ring, the requirement of machining threaded portion or an additional groove is an additional disadvantage.
In other prior art modulator units an angled seat is provided instead of a positive stop. However, the angled seat is provided to prevent nip of an O-ring seal positioned between the angled seat and a radial shoulder of the component. Importantly, the presence of an O-ring between the component and the unit housing does not allow the component to be staked in place. In this case, the component must be secured in the housing of the unit by other means, for example, by a machined threaded connection, or a press-fit, which may be less suitable for sealing of a high-pressure chamber like that of an attenuator.
Therefore, it would be desirable to retain and seal a component within an opening of a device, such as a hydraulic control unit, wherein the component is contoured to be seated and retained in such a manner as to eliminate the need for a retaining clip, require less parts and machining, optimize fluid volume chamber in the attenuator while maintaining minimal external packaging requirements, and simplify the bore design.
One aspect of the invention provides a system for retaining a component in a hydraulic control unit that includes a housing with an opening formed therein and a retaining portion adjacent the opening. The housing has an angled region formed within a bore of the opening and a component including an inner portion formed to contact the angled region at a single point and an outer portion to contact the retaining portion of the housing when the retaining portion is deformed over the outer portion.
Other aspects of the present invention provide a system wherein at least half of the outer portion is in direct contact with the retaining portion of the housing when the retaining portion is deformed. A peripheral groove can be formed on the component adapted to receive an O-ring. The inner portion of the component can be formed at an angle between about 25 to 35 degrees. The outer portion of the component can be formed at an angle between about 35 to 55 degrees.
Another aspect of the present invention provides a device for retaining pressurized fluid within a hydraulic control unit comprising a body portion, an inner portion contoured to contact an angled potion of the hydraulic control unit at a single point and an outer portion contoured to contact an integral retaining portion of the hydraulic control unit. The device can include at least half of the outer portion being in direct contact with the integral retaining portion of the hydraulic control unit. A groove can be formed about the periphery of the body portion, the groove adapted to receive an O-ring. The inner portion of the component can be formed at an angle between about 25 to 35 degrees. The outer portion of the component can be formed at an angle between about 35 to 55 degrees.
Another aspect of the present invention provides a method of retaining a component within a hydraulic control unit including inserting a component into an opening of the hydraulic control unit, contacting an inner portion of a component to an angled region of the hydraulic control unit at a single point, deforming a retaining portion of the hydraulic control unit and contacting an outer portion of the component with the retaining portion of the hydraulic control unit.
Other aspects of the method of the present invention include inserting the component into the opening of the hydraulic control unit, which includes an angled lead-in to orient the component in relation to the opening at a predetermined stack height. Contacting the inner portion of the component to the stop region of the hydraulic control unit can include preventing the component from positioning further within the hydraulic control unit. Deforming the retaining portion of the hydraulic control unit can include compressing a portion of the hydraulic control unit. Contacting an outer portion of the component with the retaining portion of the hydraulic control unit can include staking a portion of the hydraulic control unit in order to secure the component.
Another aspect of the present invention provides a system for retaining a component including means for inserting a component into an opening of the hydraulic control unit, means for contacting an inner portion of a component to an angled region of the hydraulic control unit at a single point, means for deforming a retaining portion of the hydraulic control unit to contact an outer portion of the component with the retaining portion of the hydraulic control unit. The system can include means for inserting the component into the opening of the hydraulic control unit including an angled lead-in to orient the component in relation to the opening at a predetermined stack height. The system can include means for contacting the inner portion of the component to the stop region of the hydraulic control unit that includes preventing the component from positioning further within the hydraulic control unit. The system can include means for deforming the retaining portion of the hydraulic control unit that includes compressing a portion of the hydraulic control unit. The system can include means for contacting an outer portion of the component with the retaining portion of the hydraulic control unit that includes staking a portion of the hydraulic control unit in order to secure the component.
The foregoing and other features and advantages of the invention will become further apparent from the following detailed description of the presently preferred embodiments, read in conjunction with the accompanying drawings. The detailed description and drawings are merely illustrative of the invention rather than limiting, the scope of the invention being defined by the appended claims and equivalents thereof.